Acrylic syrup and method of producing same
AssigneeMitsubishi Gas Chemical Company, Inc.
InventorsTadashi Kawabata, Shojiro Kuwahara, Masahiro Kurokawa
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Abstract
Disclosed is an acrylic syrup containing a vinyl monomer (A) of methyl methacrylate and a polymerized solid component (B) which is a high polymer of said vinyl monomer and has a weight average molecular weight of from 30,000 to 2,000,000 as measured by the GPC and a viscosity at 25° C. of from 0.1 to 50 Pa·s, wherein at least part of said polymerized solid component (B) is a grafted rubber obtained by graft-polymerizing said vinyl monomer with a rubbery polymer, and said grafted rubber has a large branching coefficient. The acrylic resin molded articles obtained from the acrylic syrup exhibit excellent impact resistance.
Claims10
An acrylic syrup having a viscosity at 25° C. of from 0.1 to 50 Pa·s and containing a vinyl monomer (A) which comprises methyl methacrylate and a polymerized solid component (B) which is a high polymer of said vinyl monomer and has a weight average molecular weight of from 30,000 to 2,000,000 as measured by the GPC, wherein at least part of said polymerized solid component (B) is a grafted rubber obtained by graft-polymerizing said vinyl monomer with a rubbery polymer, and said grafted rubber has a branching coefficient with which the inclination of a straight line obtained by double-logarithmically plotting the RMS radius (z-average inertial radius) calculated from the GPC-MALLS (gel permeation chromatography-multi-angle laser light scattering) measurement and the molecular weights, becomes 0.35 to 0.65 [nm/(g/mol)].
A method of producing an acrylic syrup comprising steps of:
- (i) preparing a starting solution by dissolving a rubbery polymer in a vinyl monomer containing at least 85% by weight of methyl methacrylate;
- (ii) heating said starting solution in a nonoxidizing atmosphere and, then, adding a chain transfer agent to said starting solution under a reflux condition;
- (iii) adding a polymerization initiator and a vinyl monomer which is for the post-addition containing at least 85% by weight of methyl methacrylate over a period of from 0.5 to 8 hours continuously or in a divided manner under a reflux condition after the chain transfer agent has been added;
- and
- (iv) continuing the heating to conduct the reflux for from 0.01 to 10 hours after the polymerization initiator and the vinyl monomer for post-addition have been added.
Dependencies are inferred from the claim text.